IMAS 2025–2026 — Middle Primary — Round 2 Question 9

In triangle $ABC$, $AB=AC=26$ cm and $BC=20$ cm. In triangle $DEF$, $DE=DF=26$ cm, where the length of $EF$ is an integer, in cm, with $EF\ne BC$. It is known that the two triangles have the same area. What is the length, in cm, of $EF$?